Step 1: Brown the Steak
Heat 2 Tbsp olive oil in a skillet over medium-high heat. Add 2 lbs sirloin steak and 2 tsp minced garlic. Sauté until the steak is browned on the outside.
Step 3: Add Sauce Ingredients
Stir in 3 Tbsp soy sauce, 1 tsp brown sugar, 2 tsp Worcestershire sauce, 1 can diced tomatoes, and pepper to taste.
Step 4: Combine and Cook (Phase 1)
Add 1 cup chopped onions and the browned beef to the crockpot. Mix well. Cook on HIGH for 3 hours or LOW for 6–7 hours.
Step 5: Add Peppers and Finish Cooking (Phase 2)
Add the 2 sliced bell peppers. Cook for an additional hour on the same setting before serving.